//--------------------------------------------------------------------------
//	Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
//  All rights reserved.
//
//	Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions are
//  met:
//
//	Redistributions of source code must retain the above copyright notice,
//  this list of conditions and the following disclaimer.
//	Redistributions in binary form must reproduce the above copyright
//  notice, this list of conditions and the following disclaimer in the
//  documentation and/or other materials provided with the distribution.
//	Neither the name of the Drew Davidson nor the names of its contributors
//  may be used to endorse or promote products derived from this software
//  without specific prior written permission.
//
//	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
//  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
//  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
//  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
//  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
//  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
//  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
//  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
//  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
//  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
//  DAMAGE.
//--------------------------------------------------------------------------
package com.feilong.lib.ognl;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Default class resolution. Uses Class.forName() to look up classes by name.
 * It also looks in the "java.lang" package if the class named does not give
 * a package specifier, allowing easier usage of these classes.
 * 
 * @author Luke Blanshard (blanshlu@netscape.net)
 * @author Drew Davidson (drew@ognl.org)
 */
public class DefaultClassResolver extends Object implements ClassResolver{

    private final ConcurrentHashMap<String, Class> classes = new ConcurrentHashMap<>(101);

    public DefaultClassResolver(){
        super();
    }

    @Override
    public Class classForName(String className,Map context) throws ClassNotFoundException{
        Class result = classes.get(className);
        if (result != null){
            return result;
        }
        try{
            result = toClassForName(className);
        }catch (ClassNotFoundException e){
            if (className.indexOf('.') > -1){
                throw e;
            }
            // The class was not in the default package.
            // Try prepending 'java.lang.'.
            try{
                result = toClassForName("java.lang." + className);
            }catch (ClassNotFoundException e2){
                // Report the specified class name as-is.
                throw e;
            }
        }
        classes.putIfAbsent(className, result);
        return result;
    }

    protected Class toClassForName(String className) throws ClassNotFoundException{
        return Class.forName(className);
    }

}
